And result in more fifth columning, which is the worst problem in the game right now, in my opinion.
While you have a point that I agree with, I picture the outcome of my 2 changes to be a bit different than you do.
Firstly, by making all undermining effects instantly take affect, the defending faction has the ability to adjust to opposition in real time. Something I feel is extremely warranted given the drastic imbalance between undermining and fortification time and credit costs when compared to their respective effects.
Second, if you only show each faction the data relevant to their undermining of a system you can eliminate what I currently see as a problem: No matter which faction undermines a system, the effect isn't just measured across all factions contributions; but all factions can see that progress at a glance. This means that Faction A may suddenly see a population of people move to undermine faction B, simply because faction C had a significant amount of opposition to faction B.
By updating the UI only to show progress made for undermining by your faction; we could drastically eliminate the effect of 5th columners affecting the decisions of others so easily. Allowing a faction to see its own undermining states in real time not only makes sense with the technology implied by Elites background, but it's the only actual way to eliminate sniping without creating other balancing concerns.
Yes, espionage would be a thing. It should be a thing. We just need a more realistic flow of information. If we neuter the ability for 5th columners to snipe we have made progress. We make information distribution more natural, we will improve things.
Fifth column activity within a faction isn't something that I see as fixable simply due to the fact that it's impossible to forcibly deny another player access to do what they want thanks to solo/group modes. All major internal "fifth column" activity I've been witness to in my faction occurred with me actively trying to prevent the activity in open, and simply being forced to watching the numbers increase at rates only possible with groups of organized players.
The fact of the matter is, with perfect stealth (group/solo), fifth column activity will always be there simply because you will never be able to see those committing the unwanted activity. Our only choices here are to make intelligent changes that help prevent the masses across all the factions from following the behavior of only one other, possibly hostile faction and eliminate the possibility of undermining sniping completely.